Waking up to the complexities of anesthesia

Elizabeth Cesar was given a peripheral nerve block, a local anesthetic that relieves pain by interrupting pain signals to the brain.

Kevin Van Paassen

Shannon Moneo

Content from: Sunnybrook Hospital

Published April 26, 2017Updated April 27, 2017

For the 15,000 patients who undergo surgery at Sunnybrook every year, pain control is always top of mind. And that's where most people think about the role of the anesthesiologist. It's true they seek to find the perfect level of sedatives and painkilling drugs for each procedure they oversee.

However, that traditional approach is expanding with the creation of The Centre for Perioperative Brain Health at Sunnybrook.

Anesthesiologists are now venturing far beyond the operating room, helping ease the anxiety and discomfort many patients feel before surgery, delivering highly specific pain control, cutting down on the side effects of narcotics, and taking aim at the confusion and memory problems many patients face long after they leave the hospital.

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BEFORE

Finding the calm before surgery

Laura Perez had never undergone surgery. Scheduled for an obstetric surgical procedure, the 40-year-old Toronto resident was understandably nervous.

Although she has uncles who are physicians and she knew she'd be in good hands, the unknown represented by the surgical ward left her uneasy. "I knew this would be something different," says Laura. But one week before her operation, she visited Sunnybrook's interactive lab where the unknown became known.

"I was given a special pair of goggles by the research assistant and told to press Play," she says. Laura then watched a six-minute virtual reality video that would take her from the first moments in the surgical ward right into the brightly lit operating room, amid comforting words from nurses and physicians.

"If I turned my head, I could see all around the room," Laura says of the video, filmed with six 360-degree cameras. "It was very informative and very calming to know what would happen." And on the day of her surgery, her angst had been dialed down by that virtual reality pre-op tour, courtesy of Dr. Fahad Alam.

Dr. Alam, an assistant professor at the University of Toronto's Department of Anesthesia, is well aware of the apprehension surgical patients feel, which can cause symptoms like high blood pressure and an elevated heart rate. This can affect as many as 80 per cent of patients, he says.

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Research has also shown that heightened anxiety results in slower healing, a greater need for medications after surgery, as well as higher death rates. This prompted Dr. Alam to align his interest in education, expertise in anesthesia and knowledge of technology to create Sunnybrook's virtual reality lab where, with a dose of creativity, his virtual reality movie was born.

To view it, patients don virtual reality goggles and circuit through the pre-op experience. They're made to feel they're on a stretcher, with nurses and physicians speaking to them, and then wheeled into the operating room, where monitors are attached, beeping begins and anesthesiologists explain what will happen. The video ends as the oxygen mask is placed on the patient's face.

"I hear 'cool' and 'ah' all the time," Dr. Alam reports. "Some say they now know what [surgery] feels like." Notes Laura, "The video would be a good experience, especially for the young or someone who's never had surgery."

Dr. Alam's team is in the process of studying a diversity of patients to measure their before-and-after anxiety levels with the hope that the six-minute chunk of virtual reality will erase weeks of pre-op jitters and lead to better post-op outcomes.

"The potential for using virtual reality is just at its start. There are so many possibilities," says Dr. Alam. "We have also started creating videos for patients to view before getting epidurals, seeing a radiologist or getting a nerve block, just to name a few examples."

DURING

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Regional versus general

All forms of anesthesia provide pain control, but in different ways. Regional anesthesia numbs just a small part of the body, and is most commonly used for minor surgeries. In contrast, general anesthesia causes the patient to become unconscious for a period of time, affecting the brain and whole body in various ways.

"Once the patient is under the intense lights of the operating room, they are administered a combination of drugs which can suppress brain function, relax muscles or facilitate mechanical breathing," says Dr. Stephen Choi, a staff anesthesiologist at Sunnybrook. "The more medications you give, the deeper the effect. It's like a light dimmer switch, but you don't want to turn things down excessively."

But these drugs, important as they are, come with possible side effects. All anesthetics can lower the heart rate and reduce blood pressure, sometimes to dangerous levels. The challenge is to give the least amount possible to facilitate surgery and keep the patient safe. After surgery, exposure to anesthetics can result in confusion and potentially long-term memory loss. That's why giving the least amount necessary is so critical, says Dr. Choi.

Along with Dr. Beverley Orser, the Department of Anesthesia's director of research, Dr. Choi, who is also an assistant professor in the University of Toronto's Department of Anesthesia, has developed ways for patients, like Elizabeth Cesar, to recover faster, use fewer painkillers and experience less pain overall.

After Elizabeth awoke from surgery for her right shoulder in 2014, she almost skipped to her car.

"I felt so good," recalls the 58-year-old Hamilton resident. "By the end of the first week, I was off pain medications."

Contrast that with her first shoulder surgery in January 2013. For eight weeks following the operation, she was taking a heavy dose of painkillers, and 10 months after surgery, she said to her doctor, "Fix my shoulder or cut it off."

Her suffering eventually led her to Sunnybrook's Holland Orthopaedic and Arthritic Centre and surgeon Dr. Patrick Henry for her most recent surgery, where an anesthesiologist applied a carefully managed nerve block to reduce pain.

Elizabeth was given a peripheral nerve block, which involves injecting a local anesthetic onto or near specific nerves for temporary pain control, to relieve pain by interrupting how pain signals are relayed to the brain.

"With the nerve block, I was able to get ahead of the pain before it became overpowering," says Elizabeth.

Dr. Choi says that orthopaedic surgery, such as Elizabeth's, is well suited to regional anesthesia. When the nerve block is administered, the patient can have no feeling in the area for up to 24 hours.

As well, when ultrasound-guided regional anesthesia (UGRA) is used, as it was in Elizabeth's case, less anesthetic, if any at all, is required so the patient's mental capacity is affected as little as possible.

With general anesthesia, mental functions can be compromised, triggering the following questions from Dr. Choi: "Does intense exposure to anesthesia induce permanent change? Are there long-lasting effects to memory? People wake up and seem normal, but are they?" As with many valuable discoveries, Dr. Choi's curiosity has been the motivation for his work with UGRA.

With UGRA, the physician can locate more accurately the specific nerve that requires anesthesia. The success rate is about 95 per cent, compared to the 85-per-cent success rate using "landmark-based" techniques, which means the nerve is in a general area and needs to be found based on physiology and past practice.

Another advantage of using regional anesthesia is its superior form of pain control. And given the growing concern about opioids – including the risks of overdose and addiction – UGRA may be better for long-term recovery, Dr. Choi points out.

The goal now, says Dr. Choi, is to train more physicians to use UGRA, which, in smaller settings such as rural hospitals, would be a significant advantage.

AFTER

Effects on memory, not forgotten

Back at Sunnybrook's Centre for Perioperative Brain Health, Dr. Orser and her team are conducting preclinical laboratory research, trying to determine what causes brain problems after surgery, like memory loss. "We have to begin by quantifying the problem," says Dr. Orser. "Patients look okay and ready to go home after surgery, but about 30 per cent may still be struggling with memory problems."

Seniors and those who have had repeated surgeries are at higher risk. Laboratory research shows that some of the drugs commonly used by anesthesiologists trigger what's known as memory-blocking receptors in the brain, notes Dr. Orser. When the receptors are activated by exposure to the anesthetic drugs or by inflammation, long-term memory loss may occur. "Such changes may contribute to the problems we see in patients after surgery. We know of people who came in for knee surgery but developed post-op deficits, such as delirium or memory loss," she says.

So far, Dr. Orser's preclinical research work has shown that when anesthesia is used and it interacts with receptors in the brain's hippocampus – considered to be the centre for emotion, memory and the autonomic nervous system – the memory-loss properties of the drugs are heightened.

"For the longest time, we assumed these drugs were eliminated and the brain goes back to the baseline," Dr. Orser says. "But that's not the case. The effects of these drugs can linger for a long time."

In order to understand the frequency and severity of the deficits in humans, Dr. Orser and her team have started a study with patients undergoing hip and knee surgery. The hope is to have more information by next year.

It's another way anesthesiologists at Sunnybrook, are venturing beyond their traditional operating-room roles to examine the interplay between surgery, medications and brain function.

"It's a change in focus for anesthesiologists," Dr. Orser points out. "We are stepping outside the operating room because we want to make the whole surgical journey better for our patients."

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